Parker posted a photo of the trio standing outside with the New York City skyline in the distance Friday.
It received more than 1 million "likes" by Saturday morning.
"Together again. Read through our first episodes.@justlikethatmax Alongside all the fellas and our newest cast members. Like an ice cream sundae. X,SJ," Parker captioned the image.
HBO Max, the streaming service behind the sequel show, also confirmed this week that Mario Cantone, Evan Handler, David Eigenberg and Willie Garson would be reprising their SATC roles in And Just Like That.
Production is to begin in New York this summer on the 10-episode, half-hour series.
SATC ran on HBO 1998 to 2004. It was followed by two films in 2008 and 2010.